Closure with protective coating and method of manufacture thereof



Aug. 20, 1968 ALI-MAN ET 3,397,661

1TH PROTECTIVE COATING AND METHOD CLOSURE W OF MANUFACTURE THEREOF Original Filed Nov. 50, 1964 2 Sheets-Sheet 1v INVENTORS .7464 (0415 All/WAN fg'f/vf fflAIVl/S [/Af I? 7' r 01?! y Aug, 20, 1968 J. c. ALLMAN ET AL 3,397, 1

CLOSURE WITH PROTECTIVE COATING AND METHOD OF MANUFACTURE THEREOF Original Filed Nov. 50, 1964 2 Sheets-Sheet 2 FIG. 4 F/G. 5

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INVENTORS JAZZ (0115 ZZMAN [3?6'!!! f0! /5 f/KE UnitedStates Patent 3,37,661 CLOSURE WITH PROTECTIVE COATING AND METHOD OF MANUFACTURE THEREOF Jack Cullen Allman, Barrington, and Eugene Francis Eike, CrystalLake, Illl, as'signors to American Can Company, New York, N.Y., a corporation of New Jersey Original application Nov. 30, 1964, Ser. No. 414,731, now Patent No. 3,245,568, dated Apr. 12, 1966. Divided and this application Aug. 16, 1965, Ser. No. 487,954

14 Claims. (Cl. 113-121) This application is a division of my co-pending application Ser. No. 414,731,'filed Nov. 30, 1964, now Patent No. 3,245,568.

This invention relates to container closures and, more particularly, it relates to a container closure having a protective coating adhered to one surface thereof and to the method of manufacturing such a closure.

The present trend in consumer packaging is directed towards convenience type packaging in which a container ma be easily opened by hand by a consumer who does not need to resort to the use of any auxiliary tools in performing such opening. Such convenience packaging has been facilitated in great measure by the use of thin aluminum closures, which, when scored, can be easily torn by hand to provide the desired opening. While such scored aluminum closures have made great advances in the art of easily-opena-ble containers, there are still drawbacks inherent with :such closures which prevent them from being completely commercially acceptable.

One such drawback involves the possibility of a raw aluminum edge cutting the fingers of the consumer who grasps them. This is partially due to the inherent sharpness of a raw metal edge and partially due to the fact that, during the manufacture of such a closure, blanking out of the closure may form burrs along such raw edges. Naturally, if such a closure is fabricated of thin tin plate, there is even an increased possibility of a consumer cutting his fingers on the raw edge;

A further drawback withsuch closures, and particularly those fabricated of aluminum, is that, due to the thinness of the aluminum stock, there is a tendency for such aluminum to tear or break along the preformed score lines in the closure. In the usual construction of such easy-open closures, a finger-engageable tab is either formed integrally with or appended to the closure so that a consumer may grasp the tab and commence opening of the container. It has been found that during such an opening operation, the tab may be bent or twisted in such a manner as to cause it to tear or break away from the remainder of the closure and, consequently, to prevent easy opening of the container.

Still a'further drawback with easy-open closures and with other closures in general, is the fact that, in most applications, some suitable form of sealing gasket or compound must be used betweenthe closure and the container. This is particularly true in the case of a closure such as 'a crown cap,'which is to be utilized on a rigid container such as a glass bottle. The conventional method for providing such a gasket was to form a separate sealing ring or gasket of cork or other suitable sealing material and to dispose that separate gasket between the crown and the bottle'Of course, the drawback with such an'operatiori was that each gasket had to be tailormade to fit thecrow'n and/or the bottle, and consequently, the cost of such a gasket was extensive due to the necessity for careful manufacture thereof.

In more recent times, there hasbeen a tendency to do away with separate sealing gaskets or rings and to utilize in their place, a flowed-in type of sealing gasket. In general, this type of gasket which may contain a foaming agent, heating the assembly to fuse the plastisol, and foam it if desired, and thereafter cooling the assembly to 3,397,661 Patented Aug. 20,

set and harden'the plastisol. This procedure is described in greater detail in US. Patent No. 3,002,641.

While this procedure and the construction resulting from it are well suited to conventional crown caps which are to be opened with a tool, they are completely unfeasible for use on digitally-openable bottle caps which have a laterally-extending or depending pull tab. With this prior art procedure, it .is virtually impossible to coat the entire inside surface of the closure, including the pull tab, because of the fluidity of the plastisol material as it is applied.

With the foregoing in mind, it is, therefore, an object of the present invention to overcome the ditficulties and deficiencies associated with the prior art and to provide in their stead an improved closure having a uniform pro tective coating thereon.

Another object of the present invention is to provide a method of manufacturing such a protectively coated closure.

Another object of the present invention is to provide a coated closure and a method for manufacturing such a closure, wherein such a closure has its raw edges protected to some degree to prevent them from cutting the hand of a consumer, wherein the strength of such a closure is increased so that no undesirable tearing can take place, and wherein no separate lining compound or gasket is needed between the closure and the container to which it is to be applied.

Another object of the present invention is to provide a method for manufacturing a protectively coated closure wherein such coating is uniformly applied to. the closure while it is in a flat'sheet stock.

Another object of the present invention is to provide a method for manufacturing a protectively coated closure, wherein said method is quick, efiicient and inexpensive.

Another object of the present invention is to provide an easy-open end closure having a protective coating thereon which increases its strength, which can be used compatibly with containers having food products therein and which serves as a sealing medium between such a closure and a container on which it is to be applied.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

The foregoing objects are attained by utilizing a manufacturing method wherein a sheet or web is provided with a layer of protective coating on one surface thereof and, subsequently, the end enclosures to be formed are stamped or blanked out of that coated web. In one preferred form of the invention, a flat sheet or web of tearable end closure material, such as aluminum or thin tin plate, is fed along a linear path and is provided with a coating of a viscous foamable plastisol material on one surface thereof. Subsequent to such a coating operation, the plastisol is heated to fuse and foam it into an expanded state. Thereafter, suitable score lines are formed at spaced intervals along the web, with such score score lines defining the ultimate portion of the closure which can manually be torn away to provide easy opening thereof. Such score lines are formed preferably through the plastisol layer and partially into the metal web. Then, end closures of suitable shape are stamped or blanked out of the coated web, with each end closure having a scored portion thereon. The stamped-out closure is thus provided with a partially scored aluminum coating defining its outer surface and an expanded plastisol layer of substantially uniform thickness defining its inner surface. A suitable forming die then shapes the closure to its cup-shaped configuration from which it can be ultimately applied over the open end of a container. Before or after application to a container, an additional step can be utilized, if needed, to further foam or to reflow the plastisol layer to heal any damage done to the plastisol layer during the forming of the closure. Such a closure is manufactured with an integral tab extending therefrom coincident with the ends of the score lines whereby, once the closure is applied to the container and is sealed thereto, manual grasping of the tab by a consumer and pulling thereof will cause that portion of the closure between the score lines to tear away from the remainder thereof thereby facilitating opening of the container.

Referring to the drawings:

FIG. 1 is a schematic side elevational view of one form of apparatus suitable for carrying out the steps of the method and for producing the article described herein;

FIG. 2 is a fragmentary side elevational view of a modified means for carrying out the coating step shown in FIG. 1;

FIG. 3 is an enlarged side elevational view of a means for carrying out the scoring step in the apparatus of FIG. 1;

FIGS. 4 and 5 are enlarged fragmentary views, shown partially in section, of that portion of the apparatus of FIG. 1 which carries out the blanking and drawing steps;

FIG. 6 is a top plan view of a closure blanked out by the apparatus of FIG. 4;

FIG. 7 is a perspective view of a finished closure drawn by the apparatus of FIGS. 4 and 5 in carrying out the method described herein; and

FIG. 8 is a perspective view, similar to FIG. 7, except that the closure is shown in a partially opened condition.

As a preferred and exemplary form of the present invention, FIG. 1 illustrates a fiat sheet or web 10 being fed longitudinally by opposed feed rollers 12, 12 which engage the opposite surfaces thereof.

The web 10 is preferably formed of a thin tearable material, such as sheet aluminum (about 0.010 in.), thin tin plate, or the like, being fed from a suitable pay-off coil or supply roll, as is conventional in the art. As the web is fed linearly along, one surface thereof passes beneath a coating means generally designated 14. The purpose of the coating means is to apply a controlled substantially uniform coating of material 16 onto one surface of the web 10*, with the characteristics of the material 16 to be presently described. For the present, it sufiices to say that the material 16 has a relatively high viscosity, e.g. about 25,000 centipoises and higher, and consequently is too viscous to be applied by conventional direct coating methods.

Accordingly, FIG. 1 shows one form of reverse roller coating mechanism generally designated 14 wherein a transfer roller 18, rotating in a clockwise direction, picks up on its surface a film of the material 16 from a reservoir 20 thereof and transfers it to the adjacent surface of an applicator roller 22 also rotating in a clockwise direction. The space between the rollers 18 and 22 is carefully adjusted to meter the amount of material 16 transferred to the roller 22. A nip exists between the applicator roller 22 and a counterclockwise rotating support or back-up roller 23 disposed adjacent to and in vertical alignment with the applicator roller. As the web 10 travels through this nip, substantially all of the metered amount of material 16 is applied to the web surface by a scraping action due to the web 10 and applicator roller 22 traveling in opposite directions whereby the web 10 is provided with a predetermined thickness of the material 16.

As is shown in FIG. 2, a modified form of coating means 14' may also be utilized with such viscous material 16. In the FIG. 2 arrangement, the reservoir 20 feeds a fountain of the material 16 directly onto one surface of the web 10. A knife-blade or doctor blade 24 is mounted above the web and depends angularly downward with its lower edge intersecting into the fountain of material 16 at an angle. As the web 10 feeds the fountain beneath the edge of the blade 24, a uniform coating of material 16 is formed upon the surface of the web. By varying the angular location of the blade 24, its edge is moved toward or away from the surface of the web 10 to be coated, and by controlling such movement, one can thereby control the thickness of the coating 16 applied to the web 10.

The composition of the coating material 16 is a foamable plastisol having a viscosity in the range generally indicated above. Such plastisol materials are generally well known in the art as compositions which can be applied in a fluid state and thereafter, upon the application of heat, will flow to coalesce the various constituents thereof together and cause a gas to be liberated from a blowing or foaming agent to form a completed, foamed plastisol. One suitable foamable plastisol composition may have the following general formula:

Ingredients: Percentage Polyvinyl chloride resin 58.5 Plasticizer 36.0 Expanding agent 1.5 Pigment 1.5 Antioxidant 0.15 Stabilizer 0.15 Release agent 2.2

In the preceding formula, the polyvinyl chloride resin may be formed of a mixture of a dispersion resin having a percentage of approximately 19.0 and an extender resin having a percentage of approximately 39.5. A suitable plasticizer which may be employed is an epoxidized linseed oil, known commercially as Epoxol 9-5. A suitable expanding agent may be azodicarbonamide, and a. suitable pigment may be titanium dioxide. The antioxidant may be formed of butyl hydroxy toluene, propyl gallate, or the like, while the stabilizer may be formed of a barium cadmium complex, or the like.

It can thus be seen that a composition in accordance with the foregoing formula provides a foamable composition which is relatively low in plasticizer. This is necessary due to the fact that the presence of a plasticizer in high quantities may create taste problems when a comestible is to be packaged within a container having a closure coated with the above formula plastisol.

Although it is possible for such a foamable plastisol to be adhered directly to the web 10 by incorporating an adhesion-promoter into the plastisol composition, as would be particularly useful when the web is fabricated of aluminum, there again arises the problem that a plastisol material containing such an adhesion-promoter may not be compatible with comestibles. Accordingly, it is considered better practice to apply an adhesion-promoting coating directly onto the surface of the aluminum web which is to be coated with the plastisol material 16. Such an adhesion-promoting coating will generally be a vinyl primer, with one such suitable primer being an acrylicepoxy-phenolic coating. Such a coating may be applied to the web before it is fed past the feed rollers 12 and hence before it reaches the coating means 14.

Once the plastisol coating has been applied by the coating means 14, the coated web feeds past or through a suitable heating oven 26 which fuses and foams the plastisol material 16 to its final state. When the coated web emerges from the oven or heating means 26, it passes beneath an air curtain or other suitable cooling means 28 which cools and thereby solidifies the foamed plastisol coating 16. The thickness of the cured or foamed plastisol layer 16 is in the order of 0.015 inch and hence the total thickness of the web, with its coating thereon, is in the order of 0.025 inch.

The coated web then feeds downward into a free loop and back up over an idler roll 30 to feed toward a scoring means generally designated 32.-As can be seen in FIG. 1 and also in FIG. 3, the scoring means 32 includes a backup die 34 which is juxtaposed beneath the uncoated surface of the web 10. A reciprocating rule die 36 is mounted in alignment over the back-up die 34 and is provided on its lower surface with shaped blade means 38. As the coated web feeds intermittently beneath the rule die 36, that die is reciprocated' to lower the blade means 38 and cause it to sever through the coating 16 and into the web to thus form a series of spaced, diverging score lines 40, as shown in FIG. 3. It can be seen that the score lines 40 extend completely through the coating 16 and only partially through the web 10 so that when a closure is finally formed with its outer surface being defined by the uncoated surface of the web 10, such an outer surface will be generally imperforate. The score lines 40 have been exaggerated in width in FIG. 3 in order to provide a satisfactory illustration. Further, the inherent resiliency of the foamed plastisol 16 will cause the coating material on opposite sides of each score line to expand together toward one another and hence to substantially enclose the score lines and thus provide partial protection to the scored metal. Although FIG. 3 has illustrated the rule die having blade means to form three spaced sets of score lines 40 within the coated web, such an arrangement is only for purposes of illustration and it should be understood that the number of blades 38, and thus the number of score lines 40, can be varied depending upon the desired length and width of the web 10 to be worked simultaneously.

After the coated web has been suitably scored by the means 32, it proceeds linearly forward toward a blanking and drawing means generally designated 42 which serves to punch out an appropriate number of fiat closure blanks from the coated web, and thereafter, to draw such flat closure blanks into the cup-shaped configuration. To properly orient the foam coated web 10 with respect to the blanking and drawing means 42 for the reasons mentioned hereinafter, the coated webis carried around a wide radius, 180 bend by suitable means (not shown) so that the exposed metal surface is disposed upwardly and the exposed foamed plastisol surface is disposed downwardly. Referring now to FIGS. 4 and 5, which illustrate the details of the blanking and drawing means 42, it can be seen that the coated web 10 passes linearly across a fiat die plate 44 which is disposed beneath the coated surface thereof. The die plate 44 is provided, at its upper surface, with a cavity '46 which extends partially therethrough. The cavity 46 serves as a blanking cavity and its shape defines the ultimate shape of the closure blank which is punched or stamped from the web 10. Disposed centrally beneath the blank cavity 46 is a second larger cavity 48 which serves as the drawing cavity in which the closure blank is ultimately converted into its cup-shaped form. A reciprocable punch means is disposed above the exposed metal surface of the web and is adapted to be moved into engagement therewith with substantial force. The punch means includes a laterally extending plate 50 having a plurality of spaced circular punches 52 depending integrally therefrom, as can best be seen in FIG. 1. Push rods 53 secured to the plate 50, vertically reciprocate the plate 50 and punches 52 under the impetus of asuitable actuating force, not shown. The lower extremity of the circular punches 52 are hollow which hollow is surrounded by a depending skirt 54 having a sharp edge 55 on the outer periphery of its free end. A downwardly disposed peripheral face 56 at the free end of the skirt 54 angles upwardly towards the interior hollow from the sharp edge 55. I To accomplish the blanking operation, each punch 52 is moved downward to cause the edge 55 to strike the upper metal surface of the web, and to sever ablank out of the web. It will .be appreciated that the shape of the sharp edge 55 and its external dimensions are substantially coincident with those of the blanking cavity 46, and it will 'thus be understood that the severing which takes place 75 during the blanking operation is effectuated due to the sharp edge or shoulder 58 which surrounds the cavity 46 and thus acts, in cooperation with the edge 55, as a shear to cut through the aluminum and plastisol layers of the coated web.

-The flat closure blank formed by such a blanking or punching operation is generally designated 60 and can be seen in greater detail in FIG. 6. While such a blank 60 can be of any suitable shape or configuration, one suitable and preferable shape is that of FIG. '6 wherein a round or circular body portion 62 has an integral tab 64 extending from one edge thereof. The score lines 40 merge into the tab portion 64 whereby, when the tab is grasped and pulled, that portion of the closure contained between the score lines can be manually torn away.

After the blanking operation has been completed, and the closure blank 60 is disposed within the blank cavity 46, the plate 50 can continue to move downward to perform a drawing operation. Continued downward reciprocation of the punch 62 causes the peripheral margin of the blank 60 to be grasped between the lower face 56 of the punch and an oppositely angled, generally upwardly disposed face 65 ofa circular, spring-mounted collar or ring 66 mounted within the die plate 44. The gripping of the blank margin between the faces 56 and 65 acts as a hold-down for the blank during the drawing operation.

As the punch 52 continues down, it depresses the ring 66 against the action of mounting springs 67 confined between a peripheral flange 68 integral with and surrounding the lower end of the ring 66 and a rigid supporting plate 69. Integral with and extending upwardly from the plate 69 through the aperture in the ring 66 is a drawing die or post- 70. As the blank 60 is moved downwardly While its margin is being gripped between the faces 56 and 65, it is drawnover the post 70 into a cup-like configuration to form the closure 71 as shown in FIG. 5. As with conventional drawing operations, the gripped margin of the blank 60 gradually withdraws from between the faces 56 and 65 as the drawing proceeds to form a smooth, Wrinkle-free side wall on the closure 71. The internal dimensions of the hollow in the punch 52 are such that a sufficient clearance is provided between the walls of this'hollow and the post 70 to permit the closure blank to be suitably cupped. This clearance can be slightly less than the combined thickness of the plate 10 and the plastisol coating 16, since the plastisol is somewhat compressible. A suitable die clearance is in the order of 0.020 inch.

It would normally be expected that the plastisol material 16 would tend to tear or peel away from the aluminum layer of the closure during the drawing operation as the blank margin is withdrawn from between the clamping or gripping faces 56, 65. However, it has been found that the foamable plastisol material has sufficient inherent resiliency and collapsibility to accomplish this without either tearing or peeling the coating. Furthermore, such inherent resiliency prevents the plastisol layer from being permanently thinned as the result of the drawing operation so that, in the final reformed closure, the plastisol' layer on the interior thereof is relatively uniform throughout and at least approximates the thickness of the fused' plastisol layer on the web 10.

After completion of the drawing operation the punch 52 under the impetus of the rods 53, and the ring 66 under the impetus of the spring 67 move upwardly towards their starting positions. The inner periphery of the ring 66 conforms closely to the post 70 so that upon upward reciprocation of the ring 66, its inner edge engages under the free edge of the closure 71 stripping it from the post 70. The closure 71 is retained and carried upwardly in the hollow in the punch 52 until the punch returns to its original starting position spaced from the die plate 44 as shown in FIG. 4. Upon reaching this position a suitable mechanism (not shown) actuates a lever 72 disposed above the plate 50 depressing a push rod 73 against the action of a compression spring 74 surrounding the upper end of the push rod 73. This depression of the push rod 73 depresses an ejector plate 75 integral with the lower end of the push rod which plate 75 is in contact with the upper surface of the closure 71 whereupon the closure is ejected from the hollow in the punch 52 allowing the closure to fall freely as best shown in FIG. 1. During the free fall, the closures 71 are moved out of the blanking and drawing means 42 and into a suitable collecting means (not shown) such as by being blown by one or more air nozzles 76 (FIG. 1).

The finally formed cup-shaped closure 71, as shown in FIG. 7, includes a body portion '77 and a depending skirt 78 from which the tab 64 extends laterally. The die plate 44 has a suitably shaped aperture or slot (not shown) to permit the tab 64 to move downwardly as the closure 71 is being formed; and the drawing operation terminates after completion of the skirt 78. The plastisol coating 16 is disposed entirely about the interior of the closure 71 covering the entire body portion 77, the skirt portion 78, and the tab portion 64. The closure 71 may be applied to any suitable form of container, with one such suitable form being a glass bottle having an annular groove about its neck into which the skirt 78 can be crimped. Such a bottle is not illustrated since it forms no part of the present invention, but rather, merely provides an environment in which the closure of the present invention may be utilized. Such a bottle is, however, shown in U.S. Patent No. 3,130,056 issued to Taylor et al., and this patent shows the manner of assembly of a closure such as the closure 71 onto the glass bottle.

After the finally formed closures 71 have been ejected from the blanking and drawing means 42 they can be transported to a suitable storage or stacking means, such as that normally utilized on a conventional closing machine. If desired, they can be passed through an oven before introduction into the closing machine to reheat the plastisol coating to assure that it flows over and seals off the score lines 40. When a container upon which a closure 71 is to be applied has been filled with a suitable comestible or other product and is thereafter introduced into the closing machine, the machine can then be operated to apply a closure 71 Over the open end of such a container and to suitably clench or secure such a closure to the container. It will be appreciated that the plastisol coating 16 on the interior of the closure not only serves as a sealing gasket to hermetically seal the closure to the container, but also serves as a protective coating on the interior of the body portion 77 to prevent any adverse reaction between the contents of the container and the aluminum or tinplate layer which forms the exterior of the body portion 77.

In FIG. 8, the closure means 71 is shown in a partially opened condition. This partially opened condition has been effectuated by manually grasping the tab portion 64 and pulling it, to thereby commence severing along the score lines 40. As that closure portion between the score lines 40 is substantially or completely torn away, the remainder of the closure 71 can easily be removed by hand to thereby open the container. As can be seen, the plastisol layer extends all the way along the interior of the tab portion 64 and, as such, strengthens that tab portion and prevents it from tearing or breaking off from the remainder of the closure during the opening operation of FIG. 8. Since the score lines 40 extend totally through the plastisol layer 16 and a substantial distance into the aluminum or tinplate layer 10 which forms the exterior of the closure 71, it will be appreciated that manual force alone will be sufficient to cause severing along such score lines. Moreover, since the score lines are disposed interiorly of the closure 71, the exterior or outer surface of the closure presents a clean and imperforate appearance which is attractive to a consumer.

Although the preferred embodiment of the instant invention described hereinbefore utilizes a foamed plastisol, it should be understood that solid or non-foamed plastisols may also be used as the coating 16.

It is thought that the invention and many of its attendant features will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of parts and that changes may be made in the steps of the method described and in their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all. of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

We claim:

.1. A blank for an easy-open end closure to be used on dispensing containers, said blank comprising:

a generally planar tearable metallic layer having a circular body portion and an integral tab portion extending therefrom;

said metallic layer having adhered to one surface thereof, a continuous uniform coating of foamed plastisol which extends entirely across said body portion and said tab portion;

said blank having a pair of spaced score lines coextensive with said tab portion and extending at least partially across said body portion; and

said score lines having a depth which extends completely through said foamed plastisol coating and partially through said metallic layer to thereby define a tear strip portion in said blank.

2. A blank as defined in claim 1 wherein said metallic layer is formed of aluminum.

3. A blank as defined in claim 1 wherein said metallic layer is formed of tinplate.

4. A method of producing a blank for an easy-open closure comprising the steps of:

longitudinally feeding a thin metallic web of easily tearable material; 7

applying a coating of foamable plastisol to one surface of said web;

heating said coated web to fuse and foam said plastisol;

cool ng said heated web to solidify said plastisol;

scoring said coated web to form spaced score lines extending through said plastisol coating and into said web; and

punching a closure blank from said web with said closure blank having two spaced score lines extending thereacross.

5 A method as defined in claim 4 wherein said applylng step is accomplished by reverse roller coating said foamable plastisol onto said web.

6. A method as defined in claim 4 wherein said applymg step is accomplished by knife-coating said foamable plastisol onto said web.

7. A method as defined in claim 4 wherein said punchmg step includes forming on said blank, an integral tab portion coextensive with said two spaced score lines.

8. A method of forming an easy-open end closure for use assembled to a dispensing container, said method comprising the steps of:

longitudinally feeding a thin metallic web of easily tearable material;

applying a coating of foamable plastisol to one surface of said web;

heating said coated web to fuse and foam said plastisol;

cooling said heated web to solidify said plastisol;

scoring said coated web to .form at least two spaced score lines extending through said plastisol coating and partially into said web;

punching a flat, tabbed closure blank from 'said coated web with the tab on said blank being in registration with said space score lines; and

drawing said flat closure blank into a cup-shaped configuration having a crown portion and a skirt 9 portion depending therefrom, with said tab projecting from said skirt portion. 9. A method as defined in claim 8 wherein said web is fabricated of aluminum.

10. A method as defined in claim 8 wherein said web is fabricated of tinplate.

11. A method as defined in claim 8 wherein the thickness of said web is in the order of 0.010 inch.

12. A method as defined in claim 8, wherein said plastisol has a viscosity of 25,000 to 30,000 centipoises 10 steps, is in the order of 0.015 inch.

10 14. A method as defined in claim 8 wherein an adhesion-promoting coating is interposed between said web and said plastisol to enhance their adherence to one another.

References Cited UNITED STATES PATENTS 3,130,056 4/1964 Taylor et a1. 113-121 XR 3,207,351 9/1965 Stuart 215-46 3,266,659 8/1966 Frankenberg 21546 CHARLES W. LANHAM, Primary Examiner.

R. D. GREFE, Assistant Examiner. 

4. A METHOD OF PRODUCING A BLANK FOR AN EASY-OPEN CLOSURE COMPRISING THE STEPS OF: LONGITUDINALLY FEEDING A THIN METALLIC WEB OF EASILY TEARABLE MATERIAL; APPLYING A COATING OF FOAMABLE PLASTIC TO ONE SURFACE OF SAID WEB; HEATING SAID COATED WEB TO FUSE AND FOAM SAID PLASTISOL; COOLING SAID HEATED WEB TO SOLIDIFY SAID PLASTISOL; SCORING SAID COATED WEB TO FORM SPACED SCORE LINES EXTENDING THROUGH SAID PLASTISOL COATING AND INTO SAID WEB; AND PUNCHING A CLOSURE BLANK FROM SAID WEB WITH SAID CLOSURE BLANK HAVING TWO SPACED SCORE LINES EXTENDING THEREACROSS. 